1. Field of the Invention
The present invention relates in general to information handling system circuit boards, and more particularly to a system and method for coupling an integrated circuit to a circuit board.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Typically, information handling systems interface a variety of components with each other through a common circuit board, such as a printed circuit board (PCB). The circuit board used to support the primary processing components of an information handling system, such as the central processing unit (CPU), is typically referred to as a motherboard. Traces running through the motherboard support rapid communication of electrical signals between pins of the CPU and pins of other components, such as the random access memory (RAM), a chipset, and slots designed to accept daughter board cards. Generally, daughter boards are cards made of a circuit board and components that perform specialized functions, such as graphics processing or network communications. In the past, processing components generally coupled to a motherboard with a socket and pin arrangement. For example, pins extending outward from the outer periphery of an integrated circuit inserted into a socket securely fastened to the motherboard and interfaced with traces running through the motherboard. More recently, in an effort to make better use of motherboard space and increase the rate at which information is communicated, the pins of the integrated circuit terminate across the lower surface of the integrated circuit. The pins couple to the motherboard traces through a series of contacts across the bottom surface of the integrated circuit, such as opposing balls of electrically conductive material. One example of such an arrangement is a ball grid array (BGA) integrated circuit which couples to a pin grid array (PGA) socket.
Although BGA chips provide improved communication speeds at the motherboard or daughter board traces, the coupling of the integrated circuit to the underlying circuit board material tends to be less secure than conventional pin coupling. For example, circuit boards made of thin plastic material tend to flex when components are pressed into place, such as when daughter boards are pressed into motherboard slots. As another example, circuit boards tend to flex when secured to an information handling system chassis, such as by tightening a screw through a hole made in the board and into a chassis coupling point. As the circuit board flexes, the integrated circuit is stressed relative to the circuit board surface. If the stress between the integrated circuit and circuit board becomes excessive, coupling material that couples the integrated circuit to the circuit board may crack or break. For example, solder ball coupling points located at the corners of the integrated circuit may crack or break so that communication between the integrated circuit and circuit board are compromised, leading to failure of the information handling system. One approach for addressing this difficulty is to add glue at the corner of the integrated circuit to increase the binding force between the integrated circuit and the circuit board. However, glue typically has poor thermal characteristics which often lead to failure. Another approach is to limit circuit board deformation when under pressure, such as by adding rubber under the circuit board. However, this increases the cost and weight of the system.